Safety latches for rotary car dumper

ABSTRACT

A rotary car dumper which inverts a laden rail car and of the type having clamps to lock it in an invertible cradle is provided with gravity-operated safety latches. In the event the clamp holding mechanisms fail, the safety latches provide positive retention of the clamps so that the car can be safely returned to its upright position.

PATENTEBmJv 23 i97l SHEET 1 0F 4 I N VILN H )RS DONALD J. HEATH WALTERL. LOPATKA JAMES W PETRIE A T TORNE YS PATENTEDuuv 23 Ian SHEET b [1F 4SAFETY LATCHES FOR ROTARY CAR BUMPER BACKGROUND OF THE INVENTION Thepresent invention pertains to railcar dumpers which invert a laden carto dump its contents. More specifically, the invention concerns thosetypes of car dumpers which use a rotary cradle to support the uprightcar and have cable-operated clamps that either partially or fully spanthe open upper side of the car to support the car when the dumper isinverted.

Generally the contents of the car are dumped before the car is inverted180 and the only load on the clamp-holding cables or ropes is the emptycar. However, if the contents of the car are frozen, the holding cableshave to support both the load of the material and the inverted car. Lackof proper cable maintenance can in time cause a cable failure under thecondition just mentioned and result in the dropping of the inverted,loaded car. The mechanical safety latches of the present inventionprovide positive retention of the clamps if the cables fail, so that thecar can be safely returned to the upright position and removed from thedumper.

The present trend is toward larger capacity cars and greater payload. Toprovide for this, a greater than normal number of car clamps are usuallyused so as to increase the factor of safety and prevent damage to carand/or dumper in the event of failure. The addition of the safetylatches of this invention is a simpler and more economical means offurnishing the required added protection than providing extra carclamps.

SUMMARY OF THE INVENTION A pair of gravity-operated safety latches arepivotally mounted on the fixed frame portion of the leading side of thecradle relative to the direction in which the cradle rotates toward aninverted dumping position, and in straddling relation to the plane ofmovement of a beam clamp. Lateral abutments of the beam lie in the planeof movement of the latches and an abutment ledge on each latch movesinto underlying relation with an abutment as the gravitating latchswings relative to the inverting cradle. Similar gravity-operatedlatches are pivoted to the beam clamp at its other end and coact withabutments carried by the fixed frame portion of the cradle. It istherefore the object of the present invention to provide mechanism forlocking the clamp arm of a rotary car dumper by pivotal latches whichare urged by gravity into positive locking relation to the clamp armwhen the dumper is inverted.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective of one type ofrotary car dumper incorporating the safety latches of the presentinvention.

FIG. 2 is a fragmentary diagrammatic perspective illustrating one of thebeam clamps shown in FIG. 1 with its safety latches and associated framestructure.

FIG. 3 is a fragmentary diagrammatic perspective of a beam clamp andsafety latch arrangement, and the actuating mechanism for the clamp.

FIG. 3A is a fragmentary view in elevation of a portion of the actuatingmechanism for the clamps.

FIGS. 4-7 are diagrammatic end elevations of the FIG. 1 car dumper, andillustrate successive operational positions from the beginning to end ofa car-dumping operation.

DESCRIPTION OF THE PREFERRED EMBODIMENT As above indicated, the presentinvention may be advantageously used with various rotary car dumperspresently being used. One such car dumper (FIG. 1) used with cars ofconstant height, as in unit train operation, includes the conventionaltransversely U-shaped rigid cradle structure 12 that interconnects endrings 14 and 16 which are supported on wheels 18in a pit 20. A railcar Ris moved in the direction of the arrow 22 onto rails 24in the cradle,following which the cradle is rotated in the direction of the arrow 26until the car is substantially inverted and its contents drop into thepit for removal by a conveyor or other apparatus.

in attaining the inverted position, an initially overhead beam clamp 30at each end portion of the cradle 12 moves automatically into clampingrelation with the upper edge portions of the sidewalls of the railcar.In the ordinary car dumper the mechanism which operates the two beamclamps provides the sole support of the inverted car. In the presentapparatus, the beam clamps are mechanically locked in place by pairs ofsafety latches 32 and 34 which in conjunction with the beam clamps 30,can assume, if necessary, the entire weight of a laden car. In theordinary dumper, if the clamp-operating mechanism breaks, the car can bedropped and damaged, whereas in the present instance the safety latcheslock and prevent damage to the clamps. Because the clamps cannot releasewhen the latches are active, no damage to the car can occur and the car,even though it may not dump, can be safely removed from the dumper.

With continued reference to FIG. 1 and to the general and knownoperating principles of the rotary car dumper 10, a reversible motor Mdrives a gearbox 33 that is connected to aligned power shafts 35 whicheach power a cable drum 36. A cable 38 on each drum is trained aroundthe associated end ring 14 or 16 to efiect rotative movement of thecradle 12.

Each beam clamp 30 is operated by individual mechanism at 40 which liesin the plane of the clamp beam, and the ensuing descriptionis typical ofeither clamp mechanism. The cradle 12 includes a fabricated initiallyupright guide post 42, best shown in FIG. 2, which is engaged byslidable clamp beam carriage 44. A horizontal pivot shaft 46 is mountedon the carriage 44 and pivotally carries one end portion of the beamclamp 30. A stop 47 on the carriage 44 limits downward pivotal movementof the clamp 30 so that the beam declines slightly and its free endportion contacts the railcar first. Clamping contact is made at thatside of the railcar by a pad 48, and at the other side by a pad 50.

The beam clamps 30 automatically engage the railcar as the cradle 12rotates. For this purpose, the free end of the clamp 30 (FIG. 3) carriesa pair of sheaves 52 which individually guide clamp-holding cables 54that are anchored to the cradle through an equalizer bar at 56.Extending through the beam, the cables 54 are trained over another pairof sheaves 58, and downward through the carriage 44. Trained aroundlower sheaves 60, the clamp-holding cables 54 then extend upward and arewound and anchored to individual portions of a winding drum 62 whichmoves with the cradle 12.

The winding drum 62, in an advanced rotative position of the cradle 12,is rotated in a clockwise direction by a massive counterweight 64, aratchet wheel 66, and a pawl 68. The counterweight swings free from thewinding drum shaft. Pawl 68 is pivoted to the counterweight at 70 and isarranged to rotate the winding drum 62 in a clockwise direction afterabout 42 of rotation of the cradle 12 to the position shown in FIG. 6.As shown in FIG. 3A, the pawl 68 is part of a lever 72 which is biasedat one end by a spring 74 in a direction urging the pawl into contactwith the ratchet wheel 66. At its other end the lever carries a roller76 which is selectively engageable by a shoe 78 to disengage the pawl.Shoe 78 is mounted on an arm 80, that is pivoted to a shaft 82, and isconnected to a line 84. The shaft 82 is fixed in the frame whichsupports the winding drum and extends across the plane of movement ofthe counterweight 64 to form a stop which limits movement of thecounterweight when the cradle 12 is upright.

The link 84 is connected to a bellcrank 86 which has a roller 88 thatrides on a short, arcuate, fixed cam track 90. A compression spring 92urges the link 84 upward, and thus urges the roller 88 toward the camtrack 90. In the upright position illustrated in FIG. 3, the bellcrank86 is held by the cam track in a position in which the link 84 is in itsdownward position, thus causing the shoe 78 (FIG. 3A) to push upwardagainst the roller 76 to hold the pawl 68 in a released position.

A bracket 94 (FIG. 3) carries the bellcrank 86 and moves with the cradle12 away from a fixed stop 95. Also mounted on the bracket 94 is a sheave96 which is engaged with a length of drum winding cable 98. One end ofthe drum winding cable is wound clockwise around andanchored to acentral part of the winding drum 62. The other end of the cable 98 issecured to the lower end of a clamp-lifting carriage 100. Acarriage-lifting cable 102 extends from the other end of the carriage100 counterclockwise around and is anchored to another portion of thewinding drum.

Carriage 100 has guide rollers that roll inside a generally tubular,arcuate guide 104, that is best shown in FIG. 5, and is provided with anabutment nose 106 which projects from the guide 104 and is arranged tostrike the top end of a fixed stop member 108. Because the abutment nose106 is engaged with the stop member 108 and the cable 98 extendsclockwise around the winding drum, the winding drum cannot rotate in aclockwise direction when the cradle 12 is upright. One end portion of aclamp-lifting cable 110 is wound counterclockwise around and anchored tothe winding drum 62, and the cable 110 is trained over a sheave 112 onthe guide post 42, and around a sheave 114 which is connected to theclamp beam carriage 44, and upward over a second sheave 112. Below thelatter sheave the cable is anchored to the guide post 42. The clamp beam30 in its raised FIG. 3 position is supported by the cable 110 becausethe winding drum 62 is locked against clockwise rotation as previouslydescribed.

It will now be apparent that as the cradle 12 rotates (counterclockwise)away from its FIG. 3 and 4 upright position, the drum-winding cablesheave 96 moves upward and the clamplifting carriage 100 remains engagedwith the stop member 108, thus releasing the winding drum 62 so itrotates clockwise and pays out the cable 110. Accordingly, the clampbeam carriage 44 is lowered by gravity toward the car R, and at about l3of rotation (the FIG. 5 position) the pad 48 of the beam clamp 30 willcontact the upper edge of the car.

At approximately 42 of rotation (the FIG. 6 position) the roller 88 ofthe bellcrank 86 is beyond the arcuate section of cam track 90 and isfree to move outward. The spring 92 thus urges the link 84 upward andthe spring 74 causes engagement of the pawl 68 with the ratchet wheel66. At this time the counterweight is free of the shaft 82. Continuedrotation of the cradle 12, accordingly, causes the counterweight 64 torotate the winding drum clockwise. This will cause the clampliftingcable 110 (FIG. 3) to pay out from the winding drum.

When the cradle 12 has rotated 90 from its initial position the windingdrum 62 is at top dead center (a position not illustrated) and furtherrotation toward dumping position causes a counterweight 116 (FIGS. 3 and6) to set a band brake 118 that locks the winding drum from furtherrotation. Before the brake comes into action at 90, the counterweight 64has rotated approximately 42 about its pivot axis, thus turning thewinding drum clockwise the same 42. This action takes up theclamp-holding cables 54 to force the clamp beam 30 against the railcarR.

From the described 90 position to the fully inverted position shown inFIG. 7 the railcar R is locked in the cradle and if the material in thecar is loose, it begins to dump into the pit 20. Dumping is usuallycompleted by the time the dumper has rotated to a I60 position. If theclamp-holding cables 54 have been properly maintained, inspected, andreplaced at proper intervals, they will safely hold the full weight ofan inverted railcar plus its contents. Thus, even if the contents of acar happen to be frozen and do not dump, the car can be safely returnedto its initial position and removed from the dumper. If the cables havenot been properly maintained, there is a danger that they might break sothat the beam clamps 30 are inoperative when supporting either a full orempty car. In the present case, the safety latches 32 and 34 lock thebeam clamps 30 so that the car cannot drop. Ordinary car dumpers withoutthe latches or other safety devices have shown that the results can behazardous to personnel and extremely destructive to the car and to thedumper apparatus, not to mention the attendant cost and inconvenience inremoving the car and repairing the damage.

With a beam-clamp type of rotary car dumper using the safety latches ofthe present invention, the free end of each beam clamp 30 is providedwith a laterally projecting abutment member 120 in the plane of each ofthe safety latches 32. The two latches 32 are pivotally mounted onaligned stub shafts 122, only one of which is shown, that are held bybrackets 124 on a fixed longitudinal frame member 126 which is a part ofthe rotatable cradle 12. Each latch 32 is of generally inverted L-shapeand is overbalanced outwardly against a stop 128 when the cradle 12 isin its initial upright position. When the cradle is inverted, anabutment ledge portion 129 of each latch 32 underlies the adjacentabutment member 120.

The latches 34 are mounted for free rotation on outer projections of ashaft 130 which carries the sheaves 58. When the cradle 12 is upright(FIG. 4), each latch 34 is substantially horizontal and rests upon astop block 132 that projects from the carriage 44. An adjacent abutment134 on the fixed guide post 42 is arranged to underlie a ledge portion136 of the latch 34 when the cradle 12 is inverted after the beam clamp30 is engaged with the car.

With reference to FIGS. 4-7, each pair of the safety latches 32 and 34cooperate with the car dumper in the following manner. A railcar R ispositioned lengthwise in the dumper. If the car is part of a unit train,its couplers are on the rotational axis A of the car dumper, and it neednot be uncoupled from the train. Cars which have their couplersdisplaced from the axis A must be uncoupled. In either case, the safetylatches 32 and 34 handle only cars of unifonn height, although thesafety latches do not prevent the dumper from handling cars of otherheights.

The operator energizes the motor M and the dumper begins to rotate inthe direction of the arrow 26. It will be noted that the clamp-liftingcable 110 tends to rotate the winding drum 62 clockwise due to theweight of the clamp beam 30. However, the drum-winding cable 98 preventsclockwise rotation because this forces the clamp-lifting carriage 100downward, and the carriage abutment nose 106 rests on the stop member108. Thus, as the winding drum 62 moves away from the stop member 108,the winding drum 62 is free to rotate clockwise. In this manner theclamp-lifting cable 110 pays off the winding drum and allows the clampbeam 30 to descend by gravity. At about 13 of rotation (the FIG. 5position) the clamp beam 30 is resting upon the sidewalls of the railcarR. The latch 32 is still overbalanced onto its stop 128 and the latch 34is, similarly, still overbalanced on its stop 132.

As soon as the bellcrank 86 is elevated far enough for its roller 88 todisengage the cam track (the 42 FIG. 6 position), the spring 92 pushesthe link 84 upward and the shoe 78 releases the pawl lever 72. Thespring 74 then pivots the lever 72 and moves the pawl 68 to engage theratchet wheel 66. While the clamp-lifting cable 110 was being payed out,the clamp-holding cables 54 were being wound on the winding drum.Accordingly, as soon as the pawl 68 is engaged with the ratchet wheel66, the winding drum cannot rotate counterclockwise without moving thecounterweight 64. The clamp beam 30 is considered locked because itcannot move away from the railcar without moving the counterweight.

Rotation of the dumper beyond the FIG. 6 position tends to swing thecounterweight 64 clockwise. This applies a torque to the winding drum toexert tension on the clamp-holding cables 54 in order to clamp therailcar R to the rails 24. The torque also provides an immediate followup" action which resets the clamp beam if the clamp beam was initiallyset against an excess surcharge of material that is crushed or dislodgedduring the dumping operation. As rotation of the dumper progresses, thepressure applied to the clamp beam 30 increases, but the total pressureis limited to the weight of an average empty car in order to avoidcrushing the sides of lighter than usual cars.

The brake 118 supplies additional emergency holding power in case partor all of the load does not dump, as may be the case if the contents arefrozen. The brake is set automatically by the counterweight 116 at andbeyond about of rotation of the dumper, and prevents reverse rotation ofthe winding drum if the total load resting on the clamp beams 30 exceedsthe holding power of the counterweight 64. 1f the counterweights aloneheld the car and frozen contents, the same pressure would be applied toall cars, and this would be likely to damage light cars. Beyond the 90rotated position of the dumper, the safety latches 32 and 34 swing awayfrom their stops 128 and 132, and begin to move toward their respectiveabutment members 120 and 134.

The contents of the car are usually completely dumped by the time thedumper has rotated about 160 from its starting position. Neither safetylatch 32 or 34 is in an effective position at this rotative position ofthe car dumper. However, if the contents of the car do not dump, it ishazardous to rely solely on the clamp-holding cables 54.

Accordingly, as the dumper rotates beyond 160 gravity causes the latches32 and 34 to swing into operative positions where the ledge portions 129and 136, respectively, lie vertically aligned with the abutments 120 and134. As shown in FIG. 7, the ledges are slightly spaced from theabutments to assure free motion of the safety latches in moving to theiroperative positions. Thus positioned, the safety latches will nowpositively prevent the railcar from dropping if the clampholding cables54 break, and in the event of such breakage will retain the beam clampsin position until the railcar is returned to a safe upright positionbecause the frictional engagement of the ledges 129 and 136 with theabutments 120 and 134 will keep the latches in their locked positions.

It will be apparent that the gravity-operated mechanical safety latches32 and 34 provide for positive retention of the beam clamps in the eventthe holding cables break, and provide a simpler and less costlyalternative than using more beam clamps to increase the safety factor.

Although the best mode contemplated for carrying out the presentinvention has been herein shown and described, it will be apparent thatmodification and variation may be made without departing from what isregarded to be the subject matter of the invention.

What is claimed is:

1. in a rotary car dumper including a railcar supporting cradle, alaterally extending overhead clamp arm and slidable means carrying saidarm into closely adjacent overlying relation with a hopper type railcarto support the car when it is invetted by the dumper; the improvementcomprising a first abutment mounted on said clamp arm, an adjacent firstsafety latch pivotally mounted in overbalanced condition on said cradle,a second abutment mounted on said cradle, and an ad jacent second safetylatch pivotally mounted in overbalanced condition on said clamp am, saidlatches being gravitationally self-rotating when the dumper is invertedto move into blocking relation with their respective abutments andprevent any substantial downward displacement of the inverted clamp armand the railcar supported by the clamp arm.

2. In a rotary car dumper including a railcar supporting cradle, alaterally extending overhead clamp arm and slidable means carrying saidarm into closely adjacent overlying relation with the upper portions ofan open top railcar to support the car when the dumper inverts therailcar, the improvement comprising a gravity-operated safety latchadjacent each end of said clamp arm, means pivotally connecting one ofsaid latches to said cradle, means pivotally connecting the other ofsaid latches to said clamp arm, abutment means mounted on said cradleadjacent the latch mounted on said clamp arm, and abutment means mountedon said clamp arm adjacent the latch mounted on said cradle, each latchbeing gravitally urged free of its associated abutment when the cardumper is upright to allow setting the clamp onto the railcar, and beingswung by gravity into blocking relation with its associated abutmentwhen the car dumper is inverted, said latches and abutmentselevationally locking said clamp arm to prevent accidental release ofthe inverted railcar.

3. Apparatus according to claim 2 in which the clamp arm latch leads inthe direction of inverting movement of the dumper and is generallyL-shaped, a latch stop supporting the leading latch in an uprightposition overbalanced away from an upright car positioned in the dumper,said leading latch thus rotating in a clockwise direction about itsassociated pivot means when the dumper is inverted to swing the free endof the latch into underlying relation with its associated abutment meanson said cradle.

4. Apparatus according to claim 3 in which the cradle latch trails inthe direction of inverting movement of the dumper and extends inwardfrom the clamp arm slide, a latch stop mounted on said clamp arm andsupporting the trailing latch in a generally horizontal position withthe car dumper upright so that the trailing latch rotates in acounterclockwise direction about its associated pivot means, and meansdefining an abutment ledge on said trailing latch, said ledge overlyingsaid clamp arm abutment means when the dumper is inverted.

5. In a rotary car dumper including an invertible cradle and transversebeam clamp arms which are end-supported on fixed frame members and spanand engage the cradle to support the inverted car while it isdischarged, the improvement comprising a first pivot shaft secured toone end portion of said clamp arm, a freely pivotable first latchmounted on said first pivot shaft, a second pivot shaft mounted on saidfixed frame members adjacent the other end of said clamp arm, a freelypivotable second latch mounted on said second pivot shaft, said firstand second latches being respectively mounted on the trailing andleading portions of said clamp arm relative to the direction ofinverting movement of said cradle, a first abutment mounted on saidfixed frame member in the plane of swinging movement of said firstlatch, and a second abutment mounted on said clamp arm in the plane ofswinging movement of said second latch, said first and second latchesbeing gravity operated when the car dumper is inverted to position aportion of said second latch under its associated abutment and a portionof said first latch over its associated abutment to prevent downwardmovement of said clamp arm.

1. In a rotary car dumper incluDing a railcar supporting cradle, alaterally extending overhead clamp arm and slidable means carrying saidarm into closely adjacent overlying relation with a hopper type railcarto support the car when it is inverted by the dumper; the improvementcomprising a first abutment mounted on said clamp arm, an adjacent firstsafety latch pivotally mounted in overbalanced condition on said cradle,a second abutment mounted on said cradle, and an adjacent second safetylatch pivotally mounted in overbalanced condition on said clamp arm,said latches being gravitationally self-rotating when the dumper isinverted to move into blocking relation with their respective abutmentsand prevent any substantial downward displacement of the inverted clamparm and the railcar supported by the clamp arm.
 2. In a rotary cardumper including a railcar supporting cradle, a laterally extendingoverhead clamp arm and slidable means carrying said arm into closelyadjacent overlying relation with the upper portions of an open toprailcar to support the car when the dumper inverts the railcar, theimprovement comprising a gravity-operated safety latch adjacent each endof said clamp arm, means pivotally connecting one of said latches tosaid cradle, means pivotally connecting the other of said latches tosaid clamp arm, abutment means mounted on said cradle adjacent the latchmounted on said clamp arm, and abutment means mounted on said clamp armadjacent the latch mounted on said cradle, each latch being gravitallyurged free of its associated abutment when the car dumper is upright toallow setting the clamp onto the railcar, and being swung by gravityinto blocking relation with its associated abutment when the car dumperis inverted, said latches and abutments elevationally locking said clamparm to prevent accidental release of the inverted railcar.
 3. Apparatusaccording to claim 2 in which the clamp arm latch leads in the directionof inverting movement of the dumper and is generally L-shaped, a latchstop supporting the leading latch in an upright position overbalancedaway from an upright car positioned in the dumper, said leading latchthus rotating in a clockwise direction about its associated pivot meanswhen the dumper is inverted to swing the free end of the latch intounderlying relation with its associated abutment means on said cradle.4. Apparatus according to claim 3 in which the cradle latch trails inthe direction of inverting movement of the dumper and extends inwardfrom the clamp arm slide, a latch stop mounted on said clamp arm andsupporting the trailing latch in a generally horizontal position withthe car dumper upright so that the trailing latch rotates in acounterclockwise direction about its associated pivot means, and meansdefining an abutment ledge on said trailing latch, said ledge overlyingsaid clamp arm abutment means when the dumper is inverted.
 5. In arotary car dumper including an invertible cradle and transverse beamclamp arms which are end-supported on fixed frame members and span andengage the cradle to support the inverted car while it is discharged,the improvement comprising a first pivot shaft secured to one endportion of said clamp arm, a freely pivotable first latch mounted onsaid first pivot shaft, a second pivot shaft mounted on said fixed framemembers adjacent the other end of said clamp arm, a freely pivotablesecond latch mounted on said second pivot shaft, said first and secondlatches being respectively mounted on the trailing and leading portionsof said clamp arm relative to the direction of inverting movement ofsaid cradle, a first abutment mounted on said fixed frame member in theplane of swinging movement of said first latch, and a second abutmentmounted on said clamp arm in the plane of swinging movement of saidsecond latch, said first and second latches being gravity operated whenthe car dumper is inverted to position a portion of said second latchunder its associated abutment and a portion of said first latch over itsassociated abutment to prevent downward movement of said clamp arm.